This invention relates to a fluid jet which uses turbulent flow to comingle yarn filaments to texturize the yarn for knitting and weaving operations in the textile industry, and more particularly, to a comingling forwarding jet which can be easily laced.
In the textile industry, turbulent flow comingling jets are sometimes known as intertangling or interlacing jets and are used to entangle yarn by intertwining multifilament, artificial threads and avoid the process of twisting. When comingled, the yarn has an undulating appearance with tight areas known as knots or nodes spaced by fluffy areas of entangled filaments. A single strand having a multitude of filaments or a plurality of strands ranging from 40-800 denier can be directed through a single jet at the same time. There are many different types of jets used today, for example, closed jets, forwarding jets and slotted jets, all of which have a yarn chamber extending the length of the jet body which accommodate various sizes of yarn and an air entry orifice which is used to direct an air flow into the yarn chamber to cause the comingling of the filaments.
The closed jet is generally the simplest in design and generally includes a body having a right cylindrical yarn chamber extending therethrough and an air entry orifice for introducing high pressure air into the chamber. The air entry orifice is normally perpendicular to the axis of the cylindrical yarn chamber. Although this type of jet is still in use today and can be used quite successfully since it is the most efficient with respect to use of air and comingling effect, it is not very versatile and must be size to a particular situation so that it can only be used with a narrow range of deniers and machine speeds. These limitations require that each time the denier or machine speed exceeds the ranges, the jet must be changed. The present invention overcomes this problem by permitting a single jet to be used with a wide range of deniers and machine speeds.
Having to lace a jet from one end to the other can produce a number of problems simply because many of the jet are located on the textile machines in areas which are difficult to access. The closed jet is usually located where there is a static lacing condition since it requires the operator to lace the thread through the yarn chamber but there are many situations where a closed fluid jet is unsuitable. Therefore, a slot jet has been developed to overcome these lacing problems. Most slot jets have a narrow, longitudinal slot extending the length of the jet body and communicating with the yarn chamber so the operator can access the yarn chamber through the slot rather than threading the yarn chamber from one end to the other. The basic problem with the slot jet is that it uses greater amounts of air and the yarn has a tendency to escape from the jet when a small finish build-up exists in the yarn chamber. Most slots are located to access the yarn chamber at 90.degree. to the air entry orifice and will reduce the efficiency of the chamber irrespective of the slot width.
It is believed that the comingling jet works in the following manner to form knots or nodes and texturize the yarn. As the yarn is directed through the yarn chamber, the pressurized air enters the chamber through the air entry orifice. Upper and lower vortexes rotating in opposite directions are formed on opposite sides of the yarn chamber centerline. In a non-forwarding jet, the vortexes direct an equal amount of air out the entry and exit end of the yarn chamber. It is also believed that the vortexes terminate at planes which are contiguous to the ends of the yarn chamber, and that the knots are formed at these termination planes. As the yarn travels through the yarn chamber, it viberates rapidly between the upper and lower vortexes with the yarns rotation depending on which vortex the yarn is entrained. The intensity of the knots is the function of the speed of rotation of the vortex which, in turn, depends upon the air pressure and the chamber configuration. The air entry orifice should be located so that its centerline intersects the centerline of the yarn chamber. If the centerlines do not intersect, one of the vortexes may be predominant and the yarn will be retained in the predominant vortex, and be twisted in one direction with no comingling.
In recent years, the industry has produced a jet which will more efficiently forward the yarn through the chamber. Basically, the forwarding jet is designed so that the vortexes at the exit end of the jet are stronger than the vortexes at the entry end of the jet. This can be accomplished by various techniques; for example, by angling the air entry orifice, by tapering the yarn chamber from the entry to the exit end or by cutting away a section of the body to produce a vent. Furthermore, these techniques can be used in combination to maximize the forwarding effect as a more efficient forwarding action is required at speeds increasing to 800 m/m. The present invention provides a new technique to produce an increased forwarding action.
Although most of the forwarding comingling jets used today are the closed chamber (i.e., no slot) type and, therefore, have no automatic threading capability, there is a forwarding slot jet on the market today. This jet has a variety of forwarding features such as a tapered chamber, angular air entry orifice and a vent. However, none of these presently used jets can satisfy a wide range of yarn descriptions and denier. Also, a jet configuration which works with one type yarn on one machine may not work on the same machine for a different yarn description or may work entirely different on another type processing machine. It has been observed that, the greater the forwarding capacity of the jet, the less comingling action, and no matter how much forwarding is required, compacting of the yarn filiaments is the primary objective of the comingling process. Another disadvantage of the forwarding jets which are of a fixed design, and thus have fixed flow characteristics, is that there is a narrow range of machine speeds.
By varying the slot, conical chamber and angle of the entry orifice, there can be an infinite number of jets, but, again, they are limited to short ranges of applications. It is, therefore, apparent that there is a need for a comingling jet for use in the textile industry which can be used with a greater range of denier sizes and varying machine speeds and can be easily laced.